Brake for revolving doors



Feb. .20, 1934.

J. H. GRAHAM BRAKE FOR REVOLVING DOORS Filed March 11, 1932 INVENTOR a/ffl/IL MZZM Patented Feb. 20, 1934 '7 UNITED STATES.

PATENT OFFICE 1,947,845 BRAKE ms REVOLVING nooas John Harry Graham, Pittsburgh, Pa. ApplicationMarch 11, 1932. Serial No. 598,190

' 2 Claims. (01. -18) My invention is found in a'brake mechanism, adapted to be included in the structure of or to be applied to a revolving door of familiar type, and adapted to be maintained in retracted and inef- 5 fective position and to be advanced thence to effective and active position when need requires," to check rotation and to prevent the spinning of the door.

The invention is illustrated in the accompanying drawing. Fig. I is a view in plan from above of a revolving door in position, having the brake mechanism applied to it; Fig. II is a fragmentary view to larger scale showing in side elevation the vane of the door, together with the braking mech- 15. anism; Fig. III is a view to still larger scale, showing in longitudinal section the brake mecha nism alone; and Figs. IV, V, and VI are views in cross-section on the planes indicated respectively by the lines IV-IV, VV, and VI-VI, 20. Fig. III.

Referring first to Fig. I, a revolving door of usual and familiar type is there shown. It includes a plurality of vanes 1, and is rotatable within a cylindrical shell 2. The shell is ported on opposite sides, as indicated at 3, 3. Each vane 1 is, along the edges which engage the shell, provided with a flap or flexible strip 4. These strips, engaging the inner surfaces of the shell within which the door revolves, are normally serviceable, both to check or dampen rotation and to seal the edges of the door against the entrance of drafts. The user of the door, entering through one of the ports 3 of the shell in which the door revolves, presses upon one of the vanes l, and by pressure rotates the door in counter-clockwise direction. Advancing as the door rotates, the user emerges through the opposite port 3 in the shell.

It is characteristic of these doors that, as they 40: continue in service, the flexible flaps 4 (which ordinarily are formed of sheets of fabric-reenforced rubber) wear out; the rubber becomes fatigued and broken, the flap becomes ineifective, and the door then, insuiiiciently restrained, tends to spin. When a door in such condition is carelessly used, it is easily set spinning by a person passing hurriedly through; and another person passing through at the same time may then, taken unaware, be hurt. It is to guard against accidents of that sort that my invention is intended.

The brake mechanism of my invention may be built into the door in any convenient way; I show it as an attachment which may be applied to an 55.1 otherwise complete door. To one or more of the vanes 1 of the door, and in this instance to each of the vanes, a casing or keeper 5 is removably secured. It is secured at the edge of the vane, conveniently near the upper end of the vane. This casing or keeper forms, essentially, a slideway for a movable member, and it conveniently is so placed that the slideway extends radially with respect tothe axis of door rotation, so that the movable member alluded to may move radially toward and from the cylindrical face of the 86 shell 2. At the rear the keeper is closed by an end wall 50.

The effective member of the brake mechanism is a block 6 of suitable elastic material. In this instance it is a block of rubber secured in a ferrule of metal. The block of rubber 6 is, in an actual instance, 5 inches long, 2 inches wide, and an inch thick. At its outer edge it is beveled, as indicated at 60, and the inclined face is the forward face, as the door rotates. The ferrule 754 includes a block 7 of steel, against which the block of rubber at its base rests; it includes a tongue of material of greater resilience, and specifically a tongue of steel 8, to afford backing and reenforcement to the block of rubber as under the stress of service it is deflected; and, accordingly, the tongue 8 supports the block of rubber on its posterior side, with respect to the direction of door rotation. The tongue 8 is secured to the block 7, as by the rivets shown. The ferrule includes also the sheath 9, conveniently of sheet metal, enveloping on three sides and to the rear the assembly of the parts 6, 7, and 8. It extends longitudinally of the parts 6 and 8 part way, leaving these parts free at their outer ends (the right-hand ends, Fig. III) and the sheath 9 is bolted through the block of rubber to the tongue 8 toward the forward end of the tongue, as shown at 10.

The block with its ferrule (in which, by the bolts 10, it is firmly secured) is adapted to slide in the keeper 5. The movement of the block is controlled by a spring 11 and a bolt 12. The spring tends to shift the block outward of keeper 5 (to the right, Fig. III) and to bring it to active 100 position, where it will engage the shell 2 as the door revolves. The bolt 12, penetrating the rear wall 50 of the keeper 5, engages a screw-threaded bore in block 7; and the bolt is turned to withdraw the block 6 within the keeper and against 1 the tension of spring 11, until (as the door revolves) it is free of engagement with shell 2. A bearing plate or lining 13 may be provided within the keeper, surrounding the ferruled block on three sides, and anchored in place by engageno ment of the turns of spiral spring 11 with its notched end wall 130.

When applied to a door the blocks 6 of the braking mechanisms are normally held retracted by bolt 12, in the position indicated in Figs. II and III. When through prolonged use of the door the flaps 4 have weakened, so that they are inefiective to prevent racing, the bolts 12 of the brake mechanisms are withdrawn to such degree as may be needed, and the springs 11 permitted to .be effective to project the blocks 6 until they effectively engage the shell 2 and by such engagement brake the rotation of the door and prevent spinning. The bolts permit a controlled projecting of the blocks 6, so that they may be nicely adjusted in position, and readjusted from time to time, to serve in most efiective manner their described end.

While manifestly the mechanism of my invention may be applied severally to one or more of the vanes of a revolving door, it will ordinarily be preferable to provide duplicate mechanisms, one for each vane.

The mechanism is one which, obviously, may be applied to either side of the vane of the door (with reversal of the block 6 within the keeper, that the tongue 8 may always constitute a rearward support for the block 6). This is indicated in Fig. I and the benefit of such an arrangement is that adjacent vanes may be collapsed and lie snugly face to face, and not be held apart =byan interposed brake device.

The shell 2 within which the door revolves, commonly formed of wood, may be provided with a bearing strip, commonly of metal, upon which the blocks 6 may, when in service, make engagement.

I claim as my invention:

1. In combination with the vane of a revolving door equipped at the edge with a flexible weather strip, a keeper, a block of elastic .material movable within the .keeper in a direction transverse to the edge of the vane, a spring arranged within the keeper and engaging the block and tending toiproject the block outwardly across the edge of the door, and adjustable means for holding said "block in position relative to the keeper with the spring under tension.

2. In a revolving door including a. ported cylindrical shell, two adjacent flap-edged vanes rotatable within such shell, and adapted to be shifted between positions of collapse in which they lie in 'faceto-face contact and of service in which they stand angularly disposed one to the other, the two vanes being equipped on opposite sides, which sides are the outer sides when the two vanes stand in positions of collapse, each with a brake device, the brake device including an extensible tongue of resilient material adapted when extended to engage yieldingly the inner face of the shell, and means for holding the tongue temporarily in retracted and inactive position.

JOHN HARRY GRAHAM. 

